Ketoconazole is the generic name for the compound (.+-.)-cis-1-acetyl-4-[4-[[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethy l)-1,3-dioxolan-4-yl]methoxy]phenyl]piperazine, having the formula: ##STR1##
Ketoconazole was originally described by Heeres et al., for instance, in U.S. Pat. No. 4,335,125, in which its principal utility was as an antifungal compound. Ketoconazole was also disclosed by Rosenberg et al. in U.S. Pat. No. 4,569,935 to be useful in the topical treatment of psoriasis and seborrheic dermatitis. Pursuant to this utility, ketoconazole has been marketed in a 2% shampoo formulation (available in the United States by prescription only) for the treatment of scaling due to dandruff. The components of this shampoo include coconut fatty acid diethanolamide, disodium monolauryl ether sulphosuccinate, colorant such as F.D. & C. Red No. 40, hydrochloric acid and/or sodium hydroxide to control pH, imidurea, laurdimonium hydrolyzed animal collagen, macrogol 120 methyl glucose dioleate, perfume bouquet, purified water, sodium lauryl ether sulphate, and ketoconazole (2%).
Although the above-described shampoo is efficacious for dandruff treatment, it was desired to improve its cosmetic attributes such as lathering and conditioning, and to develop an efficacious formulation that, if desired, could contain less than 2% ketoconazole. However, since ketoconazole is subject to slow degradation by oxidation and hydrolysis, any formulation that contains significantly less than 2% ketoconazole must be effectively stabilized in order to have an acceptable shelf life. The present invention is based on the discovery of a formulation for a ketoconazole-containing shampoo that exhibits excellent cosmetic attributes such as lathering and conditioning, and is acceptably stable to degradation so that, if desired, the shampoo can be formulated to contain less than 2% ketoconazole.